The present invention relates to apparatus to test bags to determine whether the bags are sealed closed. More particularly apparatus to detect leaks in the bags.
There is available apparatus for detecting leaks in bags, particularly detecting whether the seals at the ends of the bags and back seal are properly formed.
In the formation of bags, the bag material passes a former which forms the bag material into a tubular configuration. The product is delivered to the interior of the tubular bag material, with lengths then being cut to form discrete bags. Each end of the bag and along the tube seam is sealed. If one of the seals is faulty or the bag has an unintended aperture, product within the bag can deteriorate and/or become contaminated.
In relation to detecting faulty bags, that is bags which have a leak, there is known an apparatus which has a single probe which engages the bag and applies a force thereto. If there is a leak movement of the probe results. This movement then indicates that the bag has a leak. The bag is then subsequently rejected from a supporting conveyor.
The above known apparatus has a number of disadvantages including:
(1) having to align each bag with a respective probe;
(2) the apparatus being only suitable for bags within specific length limits; and
(3) the probe giving a false reading if it engages product within the bag.
It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages.
There is disclosed herein a probe assembly to detect faulty bags on a conveyor transporting the bags from a first location to a second location, said assembly including:
a driven belt member forming a loop, the loop having a length to extend generally parallel to and adjacent said conveyor between said first and second locations, which length is to move generally in unison with said conveyor between said first and second locations;
a plurality of probes supported on the belt member, each probe including a bag engaging portion moveably mounted on the belt member to engage one of the bags so as to be displaced thereby relative to the belt member, the probes being spaced so that each bag is engaged by a plurality of the probe members; and
a detector to detect the displacement of the probe members and to generate a signal indicative of the displacement so that profiled data in respect of each bag can be generated to aid in identifying faulty bags.
Preferably said bag engaging portions are mounted on the belt for movement generally perpendicular thereto.
In one embodiment, it is preferable for the probes to be arranged in a single row. In a further preferred form preferably the probes are arranged in a plurality of generally parallel co-extensive rows.
Preferably said detector includes a first and a second detector, the second detector being spaced down stream of the first detector in the direction of movement of the belt member.
Preferably said detector includes a mounting member attached to the belt member, with the bag engaging portion being moveably mounted in its respective mounting member.
Preferably said probe assembly further includes a probe compliance portion to engage the probes to urge the probe engaging portions towards the bags and conveyor.
Preferably the compliance portion is a roller.
There is further disclosed herein a method of detecting bags having a leak, said method including:
engaging each bag with a plurality of probes, with displacement of the probes being determined by the bags, the probes being urged into contact with the bags;
providing signals indicative of the displacement of the probes; and
electronically comparing the signals associated with each bag at different times to detect a change in configuration of the bag and therefore determine whether the bag has a leak.
Preferably said method includes moving the bags in a predetermined direction from a first location to a second location, and having the probes moved in unison with the bags when engages therewith.
In the above method, the probes are moved in a direction generally perpendicular to the direction of movement of the bags, when the probes are moving into contact with the bags.